The present invention pertains generally to methods and devices for preparing and dispensing frozen confectionery foods, such as frozen custard.
Various systems and methods have been developed for the preparation and dispensing of frozen confectionery food products, such as ice cream, milk shakes, frozen yogurt, frozen juices, frozen carbonated beverages, and, in particular, frozen custard. Machines for the preparation and dispensing of frozen custard, and similar frozen confectionery food products, typically include a liquid mix container, for storing a liquid mixture from which the final frozen or semi-frozen food product is produced, and a freezing barrel or cylinder, in which the liquid mix is frozen to a desired consistency to produce the final frozen or semi-frozen food product.
The liquid mix container and freezing barrel are connected together via a tube or some other structure for providing liquid mix from the liquid mix container to the freezing barrel. The liquid mix container may be positioned above the freezing barrel, with liquid mix fed via gravity from the liquid mix container to the freezing barrel. A valve or other metering mechanism, which may be manually or automatically operated, may be positioned between the liquid mix container and the freezing barrel to control the flow of liquid mix from the liquid mix container to the freezing barrel. Alternatively, the liquid mix container may be positioned below or in some other position with respect to the freezing barrel. In such a case, liquid mix from the liquid mix container may be pumped, e.g., using a peristaltic pump or some other pumping mechanism, from the liquid mix container into the freezing barrel. As another alternative, the liquid mix container may be pressurized to provide for the pressurized transfer of liquid mix from the liquid mix container to the freezing barrel. Liquid mix within the liquid mix container may be refrigerated to maintain the quality of the mix in the mix container before it is provided to the freezing barrel. Cooling of the liquid mix in this manner may be provided by refrigeration coils wrapped around or otherwise positioned adjacent to the liquid mix container, or by positioning the liquid mix container within a refrigerated chamber.
The freezing barrel, for freezing the liquid mix to a desired consistency, is typically cylindrical in shape. Liquid mix from the liquid mix container is typically admitted into one end of the freezing barrel, and a frozen confectionery product, e.g., frozen custard, is dispensed from the opposite end of the freezing barrel. Back and front plates, which may be removable, seal the back and front ends of the freezing barrel. Liquid mix is admitted into the freezing barrel, typically through an aperture formed in or near the back sealing plate. The frozen or semi-frozen confectionery product formed in the freezing barrel is dispensed through a dispensing aperture formed in the front sealing plate thereof. Typically, a valve or gate structure is provided for closing the dispensing aperture formed in the front sealing plate, thereby enabling an operator to control the flow of frozen or semi-frozen product therefrom.
A rotatable mixing mechanism, sometimes referred to as a dasher, is disposed within the freezing barrel, typically along a central axis thereof. The mixing mechanism typically includes a mixing mechanism shaft, which is mounted at one end thereof for rotational movement in the front sealing plate and at the other end thereof at the back sealing plate. A motor, typically an electric motor, is positioned adjacent to the back sealing plate, typically outside of the freezing barrel, and is coupled through a seal structure to the mixing mechanism shaft, thereby to rotate the shaft. Blades of various sizes and shapes may be mounted to the mixing mechanism shaft within the freezing barrel. The blades mounted to the shaft may be designed for several purposes, including the mixing of liquid mix within the freezing barrel, the scraping of frozen product from the inner peripheral surface of the freezing barrel, and the providing of an auger mechanism for moving mix from the back of the freezing barrel to the front thereof, wherefrom the final frozen or semi-frozen food product is dispensed.
The freezing barrel is chilled, typically by refrigerant evaporator coils wrapped around the freezing barrel or by a refrigerant evaporator barrel or chamber formed around the freezing barrel and through which refrigerant is pumped. The entire freezing barrel, except for the back and front ends thereof, including any evaporator coils or chamber surrounding the freezing barrel, is typically encased in a thermally insulating material, such as foam, thereby to provide more efficient chilling of the freezing barrel, and to minimize the effect of ambient environmental temperatures on the freezing barrel temperature. As liquid mix is driven by the rotating mixing mechanism from the back end to the front end of the chilled freezing barrel, the liquid mix is frozen to a desired consistency to be dispensed from the front end of the freezing barrel.
Various systems and methods have been devised for controlling the combined process of providing liquid mix to a freezing barrel, mixing the mix in and propelling the mix through the barrel, freezing the mix in the barrel as it is propelled therethrough, and dispensing a frozen product from the freezing barrel, to ensure that the final frozen food product produced by the combined process has the desired consistency and quality. For example, many frozen food products (e.g. soft serve ice cream, milk shakes, etc.) are dispensed serving by serving from the freezing barrel of the machine in which they are produced. To maintain a desired amount of mix within the freezing barrel, to provide a desired quantity and quality of product, some systems monitor operation of a dispensing mechanism provided at the front end of the freezing barrel. By monitoring when, or for how long, the dispensing mechanism is opened, or an amount of product dispensed through the dispensing mechanism, the providing of liquid mix into the freezing barrel may be controlled in response thereto to maintain a desired amount of mix in the freezing barrel. Other systems have monitored the weight of material in the freezing barrel, or the pressure within the freezing barrel, and have controlled the providing of liquid mix into the freezing barrel to maintain a desired weight or pressure of material within the barrel. Systems have also used thermistors or other temperature sensors to monitor temperatures within the freezing barrel, and have employed such temperature monitoring to control the refrigeration system providing chilling to the freezing barrel, thereby to maintain the freezing barrel and, therefore, the contents thereof, at a desired temperature. Still other systems have monitored the speed of rotation of the rotatable mixing mechanism positioned in the freezing barrel, or the amount of work required to drive the mixing mechanism (which may be measured by monitoring current flow to an electric motor driving the mixing mechanism), to determine the consistency of the product within the freezing barrel, and to adjust operation of the system (e.g. chilling temperature and mixing mechanism rotation) in response thereto.
Some machines for producing frozen or semi-frozen food products provide for different modes of operation of the machine. For example, the freezing barrel temperature and/or speed of mixing mechanism rotation may be controlled automatically by the machine to different temperature levels and speeds depending upon whether the machine is in, e.g., a production mode, where a frozen food product is being produced by the machine, a hold mode, where a frozen or semi-frozen product within the freezing barrel is maintained at a desired consistency without more product being made, a cleaning mode, where water or some other cleaner is passed through the freezing barrel to clean and sterilize it, or a pasteurization mode, where a liquid mix is actually heated in the freezing barrel to a desired temperature. An operator may typically select the desired mode of operation, e.g., using a user input device provided on the machine.
Frozen custard is typically produced as a continuous process by a frozen custard machine. Rather than providing for the dispensing of individual servings, frozen custard is typically produced by a frozen custard machine at a continuous production rate. Thus, during the production of frozen custard, there is a continuous flow of liquid mix into the freezing barrel of the frozen custard machine, and a corresponding flow of frozen custard out of the freezing barrel. The frozen custard typically flows from the freezing barrel of the frozen custard machine out of a dispensing aperture formed in the front of the freezing barrel and down a chute into a chilled dipping cabinet. Servings of frozen custard are hand-dipped from the frozen custard that is stored temporarily in the dipping cabinet. In such a system, a degree of refrigeration provided to the freezing barrel is set so as to freeze the frozen custard mix passing through the freezing barrel to a desired consistency for a pre-set production rate.
Frozen custard, like many other frozen confections, is best, i.e., has the best taste, texture, and appearance, when served soon after it is produced, e.g., by a frozen custard machine. Thus, frozen custard should not be stored for a long period of time in the dipping cabinet before being served. (The egg yolks which are one ingredient of frozen custard may cause the frozen custard to discolor if not served promptly after it is produced by the frozen custard machine.) This can pose a problem when trying to pre-determine the appropriate production rate for a frozen custard machine. The frozen custard machine production rate must be sufficient to provide an adequate supply of fresh frozen custard during times of high demand. Failure to produce custard at a sufficient rate during times of high customer demand could result in missed sales. During periods where there is no customer demand, production of frozen custard by the frozen custard machine can be stopped entirely. For example, the frozen custard machine may be put in a hold mode, wherein the flow of custard through the freezing barrel is suspended, and wherein refrigeration of the freezing barrel is maintained at a level to keep the custard currently in the freezing barrel at a desired temperature level in anticipation of the resumption of production. During periods of intermediate customer demand, however, production of custard by the custard machine at a pre-set level to meet maximum customer demand will out-strip the current demand. This could result in wasted product. If the excess product produced during periods of lesser demand is saved for too long, for example, in a dipping cabinet, the quality thereof will degrade to a point where it should not be served to customers. Not producing any product during periods of lower demand could result in missed sales.
Therefore, what is desired is a method and machine for producing frozen custard, and similar frozen confections, which provides for the production of fresh frozen product of a desired consistency and quality at production rates which may be adjusted in response to current customer demand. The desired machine for producing frozen custard, or another similar frozen confection, should automatically adjust all operating parameters thereof so as to produce a frozen confectionery product of a desired quality and consistency at whichever production rate is selected by an operator of the machine.
The present invention provides a method and a machine for producing frozen custard or other frozen or semi-frozen confectionery products at a plurality of operator selectable production rates such that a rate of continuous production of the frozen product may be selected to correspond to customer demand at any given time. Thus, frozen custard, or a similar product, produced by a method or machine in accordance with the present invention, may be served fresh to customers, with sufficient production guaranteed to meet varying customer demand, and with a minimum of wasted product. A frozen custard or other machine in accordance with the present invention is easily controlled by an operator to select a production rate at a desired level. Based on the desired production rate selected by the operator, a frozen custard- or other machine in accordance with the present invention automatically adjusts various operating parameters of the machine to provide frozen custard or another similar product of a desired and consistent quality and consistency, regardless of the production rate selected. In accordance with the present invention, an operator is preferably also able to make manual adjustments in selected operating parameters, to fine tune product quality and consistency at each selected production level.
The present invention may preferably be implemented in a frozen custard or similar machine including one or more freezing barrels mounted in a machine cabinet. A plurality of freezing barrels may be provided in a single cabinet to provide a frozen custard machine in accordance with the present invention which is capable of producing several differently flavored frozen custards at the same time (one flavor in each barrel). Liquid mix for each freezing barrel is preferably stored in a liquid mix hopper container. The liquid mix hoppers are preferably stored in a refrigerated compartment, which may be positioned below the freezing barrels in the machine cabinet, and which is easily accessible through a door in the machine cabinet. The liquid mix hoppers are preferably easily removable from the refrigerated compartment for refilling and cleaning. Containing the liquid mix in the hoppers in a refrigerated compartment ensures that the mix remains fresh and pre-chilled to a desired temperature before being provided to a freezing barrel.
Liquid mix preferably is provided from a liquid mix hopper container to a corresponding freezing barrel via a flexible tube extending from the hopper to a coupling structure in fluid communication with a filling aperture formed through a back sealing plate of the freezing barrel. A peristaltic pump is preferably employed to pump liquid mix through the flexible tube from the hopper to the freezing barrel in a sanitary manner.
A rotatable mixing mechanism or dasher, which includes a dasher shaft, to which dasher blades are mounted, is positioned axially within the freezing barrel. One end of the dasher shaft is mounted for rotational movement in a front sealing plate of the freezing barrel. The other end of the dasher shaft is coupled through a seal in a back sealing plate of the freezing barrel to an electric dasher motor for rotation of the dasher in the freezing barrel. Rotation of the dasher mixes the mix within the freezing barrel to ensure uniform freezing thereof and propels the frozen custard mix through the freezing barrel to be dispensed in final frozen form through a dispensing aperture formed in the front sealing plate thereof. A cut-off gate may be provided at the dispensing aperture of the freezing barrel to close the dispensing aperture during periods when frozen custard is not in production. Frozen custard dispensed through the dispensing aperture formed in the front sealing plate may be directed via a chute into a refrigerated dipping cabinet, from which the frozen product is scooped into cones or bowls for distribution to customers.
Chilling of the liquid mix in the freezing barrel to a frozen state is provided by circulating refrigerant around an outer surface of the freezing barrel. An evaporator chamber preferably is formed around the outer elongated surface of the freezing barrel, through which the refrigerant is pumped. The elongated outer surface of the freezing barrel, including the refrigerant evaporator chamber surrounding the freezing barrel, preferably is encased in a thermally insulating material (such as foam) to ensure efficiency in chilling of the freezing cylinder and to minimize the impact of ambient environmental temperature conditions on operation of the system and product quality/consistency.
A frozen custard or other machine in accordance with the present invention preferably includes a user interface which allows an operator to select a rate of production of the machine. For example, an operator preferably is able to employ the user interface to select from among at least two production rates, such as a high production rate, to meet high current customer demand, or a low production rate, to meet a lesser level of current customer demand. Whichever rate of production, high or low, is selected, the quality and consistency of the frozen product produced by the machine should be the same. In accordance with the present invention, in response to the selection of a production rate by an operator using the operator interface, a system controller automatically adjusts operating parameters of the frozen custard machine to ensure production of a frozen or semi-frozen food product having the desired qualities at the selected production rate.
In accordance with the present invention, three operating parameters preferably are adjusted automatically by a system controller in response to the desired production rate selected. These three parameters are: the rate at which liquid mix is provided to the freezing barrel, the speed at which the dasher is rotated to propel mix through the freezing barrel, and the freezing temperature of the freezing barrel. For lower production rates, the rate at which liquid mix is provided to the freezing barrel is reduced and the speed of rotation of the dasher shaft is reduced correspondingly to reduce the rate at which the product is propelled through and dispensed from the freezing barrel. Conversely, for higher production rates, the rate at which liquid mix is provided to the freezing barrel is increased, and the dasher shaft rotation speed is increased to propel product through and out of the freezing barrel at an increased rate. The rate at which liquid mix is provided to the freezing barrel may be adjusted by adjusting the pumping rate, e.g., of the peristaltic pump, which is used to pump the liquid mix from a liquid mix hopper container to the freezing barrel. Similarly, dasher shaft rotation speed may be adjusted by adjusting the speed of operation of the dasher motor employed to drive the dasher shaft.
In accordance with the present invention, the freezing temperature of the freezing barrel preferably is also adjusted in accordance with the selected production rate to ensure that the frozen product produced at the selected production rate has a desired and consistent consistency. At higher production rates, the freezing temperature of the freezing barrel is reduced to ensure that the liquid mix is thoroughly frozen to a desired consistency by the time it reaches the dispensing aperture at the front end of the freezing barrel. Conversely, at lower production rates, the freezing temperature of the freezing barrel must be increased. If a too low freezing temperature is employed during a lower production rate, the mix in the freezing barrel may freeze up solid, thereby stopping production entirely.
In accordance with the present invention, the freezing barrel temperature preferably is adjusted in accordance with the selected production rate by the system controller by controlling the refrigeration system which provides refrigerant to the refrigerant evaporator chamber surrounding the freezing barrel. Preferably, the freezing barrel temperature may be controlled by controlling the pressure of refrigerant provided to the refrigerant evaporator chamber surrounding the freezing barrel. For higher production levels, refrigerant of a lower pressure level is provided to the refrigerant evaporator chamber. The lower pressure refrigerant results in more rapid removal of heat from the freezing barrel and its contents. For lower production levels, refrigerant is provided to the refrigerant evaporator chamber surrounding the freezing barrel at a higher refrigerant pressure level. This results in less rapid heat removal from the freezing barrel and its contents.
Adjustment of the pressure level of the refrigerant provided to the evaporator chamber surrounding the freezing barrel may be accomplished by providing pressurized refrigerant to the evaporator chamber via one selected path of a plurality of refrigerant paths operating at different pressure levels. For example, for a frozen custard or other machine in accordance with the present invention which may be operated at either a high production rate or a low production rate, refrigerant lines may be provided for providing pressurized refrigerant from a source of pressurized refrigerant (e.g., a remote condensing unit) to the refrigerant evaporator chamber surrounding the freezing barrel via either a lower pressure refrigerant path (for high production rates) or a higher pressure refrigerant path (for lower production rates). The pressure of the refrigerant in the evaporator chamber may be controlled with an automatic expansion valve (e.g., 20-24 PSIG) in the low pressure refrigerant path. An evaporator pressure regulator (EPR) valve may be employed to control pressure of the refrigerant provided to the evaporator chamber in the higher pressure refrigerant path (e.g., 36-40 PSIG). A solenoid operated valve, operated by the system controller in response to the production mode selected, may be used to direct refrigerant to the freezing barrel through either the lower pressure or higher pressure refrigerant path. Thus, by controlling the pumping rate of the pump providing liquid mix to the freezing barrel, the speed of operation of the dasher motor driving the dasher shaft, and the valve directing the path of refrigerant provided to the evaporator chamber surrounding the freezing barrel, a system controller of a frozen custard or other machine in accordance with the present invention automatically adjusts all of the machine operating parameters necessary to produce frozen custard or another similar frozen food product at an operator selected variable production rate while maintain desirable product qualities.
The user interface of a frozen custard or other machine in accordance with the present invention preferably allows an operator of the machine to select the desired production rate as well as to monitor operating conditions of the machine at the selected production rate and to adjust manually certain operating parameters of the machine in response to such monitored conditions. For example, a frozen custard or other machine in accordance with the present invention may include a thermister or other temperature sensing device mounted in or near the freezing barrel for monitoring the temperature of the frozen product produced therein. Such a temperature sensor preferably may be provided at the dispensing aperture of the freezing barrel, thereby providing for monitoring of the temperature of the final frozen product as dispensed through the aperture. Temperature information provided by the temperature sensor may be provided to the user interface and displayed thereon.
Using such product temperature information, along with the operator""s own observation of the product being dispensed from the machine, the operator may determine that a slight adjustment in one or more of the machine operating parameters is required to maximize the quality and/or consistency of the product being dispensed by the machine. Thus, although the operating parameters (rate at which liquid mix is provided to the freezing barrel, dasher speed, and freezing barrel temperature) may be established automatically by the machine in response to the selection of a desired production rate, the machine preferably allows the operator to make slight adjustments to one or more of those parameters to fine tune production if required or desired. For example, a frozen custard or other machine in accordance with the present invention may automatically select a first delivery rate of liquid mix from a liquid mix container to the freezing barrel in response to a user selecting a high production rate and a second delivery rate of liquid mix from the liquid mix container to the freezing barrel in response to the operator selecting a lower production rate. In accordance with the present invention, the user interface preferably allows the operator to adjust the delivery rate of the liquid mix from the liquid mix container to the freezing barrel over a limited range of delivery rates around the first delivery rate or the second delivery rate, thereby to make slight adjustments in the delivery rate from the automatically set first or second delivery rate. Similarly, a frozen custard or other machine in accordance with the present invention may automatically set a first dasher speed in response to an operator selecting a high production rate and a second dasher speed in response to an operator selecting a lower production rate. In accordance with the present invention, the machine user interface preferably allows the operator to adjust the dasher speed for a limited range of dasher speeds around the automatically set first or second dasher speed. This ability manually to adjust selected operating parameters, such as the delivery rate of liquid mix from the liquid mix container to the freezing barrel and the dasher speed, for a limited range of values around automatically set values of those parameters, allows an operator to fine tune operation of the machine to optimize the quality of the frozen food product produced by the machine.
The user interface also preferably may provide other information related to operation of the frozen custard or other machine to the operator. For example, the user interface preferably provides a warning indication to the operator when the level of liquid mix in a liquid mix hopper container runs low. Preferably, a device is employed for monitoring a level of liquid mix in the liquid mix hopper which accurately measures the liquid mix level in the container while requiring low maintenance. In accordance with the present invention, an ultrasonic sensor may be employed to monitor a level of liquid mix in a liquid mix hopper. For example, an ultrasonic sensor may be mounted on the refrigerated compartment in which the liquid mix hopper is positioned. The ultrasonic sensor may be positioned in a fixed position on the refrigerated compartment so as to direct an ultrasonic signal downward toward the surface of the liquid mix in a liquid mix hopper positioned within the compartment below the sensor, and to detect the rebounded ultrasonic signal from the liquid mix surface. The ultrasonic sensor thus is capable of detecting a level of liquid mix in the liquid mix hopper without physically contacting the liquid mix. Unlike other conventionally employed fluid level measuring devices, such as a float mechanism, the ultrasonic sensor does not need to be cleaned periodically and risk of contamination of the liquid mix is reduced. The ultrasonic sensor may provide a signal related to the detected level of liquid mix to the system controller. The system controller monitors the liquid mix level signal, and provides preferably an audible and visible warning indication to the operator when the level of liquid mix in the liquid mix hopper is low, indicating, therefore, that additional liquid mix should be added to the liquid mix hopper.
Besides allowing for the selection of a desired production rate, the user interface of a frozen custard or other machine in accordance with the present invention preferably also allows an operator to select other operating modes of the machine. Such other operating modes may include a cleaning mode, during which water and/or a cleaning solution is directed through the freezing cylinder, and a hold mode, in which production of new frozen product by the machine is stopped, but frozen product in the freezing barrel is maintained at a desired temperature in anticipation of resumed production at any time. In accordance with the present invention, the system controller automatically controls operating parameters, e.g., liquid mix pump speed, dasher speed, and freezing barrel temperature, as required for implementation of the operating mode selected.
Further objects, features, and advantages of the invention will be apparent from the following detailed description taken in conjunction with the accompanying drawings.